A major and ongoing problem for petroleum and chemical industries is the inability of present-day technology to precisely find leaks in transportation and storage facilities. The problem has two major components: the first challenge is to establish that a facility is in fact leaking; the second challenge relates to accurately locating the source of a leak. It is the second of these two issues that the present invention addresses.
More than thirty different techniques are known in the art for leak-detection. These methods can be grouped into several categories depending on the technology used. Some of these categories are systems based on: odorants, radioactive or chemical tracers, acoustic signals, dyes, smart pigs, electromagnetics, computer product mass-balance, hydrostatic testing, transient pressure-wave monitoring, reflectometry, thermal and infrared, and diffusion.
Although these conventional methodologies have enjoyed some degree of success in finding leaks, none has shown a capability to consistently and precisely locate pin-hole leaks, particularly in subsurface pipelines and associated facilities. In many cases, underground facilities are determined to be leaking only after material mass-balance has indicated that substantial loss of product has occurred, or when material escaping from a leak rises to the soil surface and is visually detected. In both cases, such lack of precision can result in appreciable pollution, as well as in high economic costs incurred through direct loss of product.
One strategy traditionally used to locate leaks in pipelines involves the addition of an odorant to a pipeline hydrostatic test-fluid, followed by attempts to detect the odorant at ground level. This technique has generally been unsuccessful for several reasons. Firstly, conventional instrumentation such as gas detectors ("sniffers") or gas chromatographs lack the sensitivity and/or field-portability required to detect the low concentrations of odorant which typically reach the surface. Secondly, and of critical importance, is that the mercaptan odorants usually employed in this technique are water-soluble, and migrate with the aqueous phase of the standard test-fluid, to give imprecise or erroneous locations for leaks. Even when such odorant-based techniques are partially "successful", their overall lack of precision may impose substantial economic penalties via the increased costs in equipment and manpower required to excavate over a generalized area to pinpoint the precise source of a leak.
Therefore, there exists an industry need for a leak-detection system capable of consistently and accurately locating leaks in underground, and/or above ground, facilities. The present invention constitutes a novel leak-detection test-fluid which has shown to be capable of very accurately locating leaks in either above-ground facilities, or in buried pipelines or associated facilities.